cc: Use BeginFrameArgs

cc/trees/thread_proxy.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/thread_proxy.h"
 
 #include <string>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
@@ skipping 59 matching lines @@
       commit_requested_(false),
       commit_request_sent_to_impl_thread_(false),
       created_offscreen_context_provider_(false),
       layer_tree_host_(layer_tree_host),
       started_(false),
       textures_acquired_(true),
       in_composite_and_readback_(false),
       manage_tiles_pending_(false),
       weak_factory_on_impl_thread_(this),
       weak_factory_(this),
+      frame_did_draw_(false),
       begin_frame_sent_to_main_thread_completion_event_on_impl_thread_(NULL),
       readback_request_on_impl_thread_(NULL),
       commit_completion_event_on_impl_thread_(NULL),
       completion_event_for_commit_held_on_tree_activation_(NULL),
       texture_acquisition_completion_event_on_impl_thread_(NULL),
       next_frame_is_newly_committed_frame_on_impl_thread_(false),
       throttle_frame_production_(
           layer_tree_host->settings().throttle_frame_production),
       begin_frame_scheduling_enabled_(
           layer_tree_host->settings().begin_frame_scheduling_enabled),
@@ skipping 20 matching lines @@
   TRACE_EVENT0("cc", "ThreadProxy::CompositeAndReadback");
   DCHECK(IsMainThread());
   DCHECK(layer_tree_host_);
   DCHECK(!defer_commits_);
 
   if (!layer_tree_host_->InitializeOutputSurfaceIfNeeded()) {
     TRACE_EVENT0("cc", "CompositeAndReadback_EarlyOut_LR_Uninitialized");
     return false;
   }
 
-  // Perform a synchronous commit.
+  // Perform a synchronous commit with an associated readback.
+  ReadbackRequest request;
+  request.rect = rect;
+  request.pixels = pixels;
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
     CompletionEvent begin_frame_sent_to_main_thread_completion;
     Proxy::ImplThreadTaskRunner()->PostTask(
         FROM_HERE,
-        base::Bind(&ThreadProxy::ForceCommitOnImplThread,
+        base::Bind(&ThreadProxy::ForceCommitForReadbackOnImplThread,
                    impl_thread_weak_ptr_,
-                   &begin_frame_sent_to_main_thread_completion));
+                   &begin_frame_sent_to_main_thread_completion,
+                   &request));
     begin_frame_sent_to_main_thread_completion.Wait();
   }
   in_composite_and_readback_ = true;
+  // This is the forced commit.
+  // Note: The Impl thread also queues a separate BeginFrameOnMainThread on the
+  // main thread, which  will be called after this CompositeAndReadback
+  // completes, to replace the forced commit.
   BeginFrameOnMainThread(scoped_ptr<BeginFrameAndCommitState>());
   in_composite_and_readback_ = false;
 
-  // Perform a synchronous readback.
-  ReadbackRequest request;
-  request.rect = rect;
-  request.pixels = pixels;
-  {
-    DebugScopedSetMainThreadBlocked main_thread_blocked(this);
-    Proxy::ImplThreadTaskRunner()->PostTask(
-        FROM_HERE,
-        base::Bind(&ThreadProxy::RequestReadbackOnImplThread,

[brianderson, 2013/07/18 02:02:49]

This method has been made part of ForceCommitForReadbackOnImplThread to avoid
race conditions where we might commit and draw for readback before the Impl
thread has the readback request.

-                   impl_thread_weak_ptr_,
-                   &request));
-    request.completion.Wait();
-  }
+  request.completion.Wait();
   return request.success;
 }
 
-void ThreadProxy::ForceCommitOnImplThread(CompletionEvent* completion) {
-  TRACE_EVENT0("cc", "ThreadProxy::ForceCommitOnImplThread");
+void ThreadProxy::ForceCommitForReadbackOnImplThread(
+    CompletionEvent* begin_frame_sent_completion,
+    ReadbackRequest* request) {
+  TRACE_EVENT0("cc", "ThreadProxy::ForceCommitForReadbackOnImplThread");
   DCHECK(IsImplThread());
   DCHECK(!begin_frame_sent_to_main_thread_completion_event_on_impl_thread_);
+  DCHECK(!readback_request_on_impl_thread_);
 
-  scheduler_on_impl_thread_->SetNeedsForcedCommit();
-  if (scheduler_on_impl_thread_->CommitPending()) {
-    completion->Signal();
-    return;
-  }
-
-  begin_frame_sent_to_main_thread_completion_event_on_impl_thread_ = completion;
-}
-
-void ThreadProxy::RequestReadbackOnImplThread(ReadbackRequest* request) {
-  DCHECK(Proxy::IsImplThread());
-  DCHECK(!readback_request_on_impl_thread_);
   if (!layer_tree_host_impl_) {
+    begin_frame_sent_completion->Signal();
     request->success = false;
     request->completion.Signal();
     return;
   }
 
   readback_request_on_impl_thread_ = request;
-  scheduler_on_impl_thread_->SetNeedsRedraw();
-  scheduler_on_impl_thread_->SetNeedsForcedRedraw();
+
+  scheduler_on_impl_thread_->SetNeedsForcedCommitForReadback();
+  if (scheduler_on_impl_thread_->CommitPending()) {
+    begin_frame_sent_completion->Signal();
+    return;
+  }
+
+  begin_frame_sent_to_main_thread_completion_event_on_impl_thread_ =
+      begin_frame_sent_completion;
 }
 
 void ThreadProxy::FinishAllRendering() {
   DCHECK(Proxy::IsMainThread());
   DCHECK(!defer_commits_);
 
   // Make sure all GL drawing is finished on the impl thread.
   DebugScopedSetMainThreadBlocked main_thread_blocked(this);
   CompletionEvent completion;
   Proxy::ImplThreadTaskRunner()->PostTask(
@@ skipping 179 matching lines @@
   Proxy::MainThreadTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&ThreadProxy::DidCompleteSwapBuffers, main_thread_weak_ptr_));
 }
 
 void ThreadProxy::SetNeedsBeginFrameOnImplThread(bool enable) {
   DCHECK(IsImplThread());
   TRACE_EVENT1("cc", "ThreadProxy::SetNeedsBeginFrameOnImplThread",
                "enable", enable);
   layer_tree_host_impl_->SetNeedsBeginFrame(enable);
+  layer_tree_host_impl_->UpdateBackgroundAnimateTicking(!enable);
 }
 
 void ThreadProxy::BeginFrameOnImplThread(const BeginFrameArgs& args) {
   DCHECK(IsImplThread());
   TRACE_EVENT0("cc", "ThreadProxy::BeginFrameOnImplThread");
+
+  base::TimeTicks monotonic_time =
+      layer_tree_host_impl_->CurrentFrameTimeTicks();
+  base::Time wall_clock_time = layer_tree_host_impl_->CurrentFrameTime();
+  layer_tree_host_impl_->Animate(monotonic_time, wall_clock_time);
+
+  // Reinitialize for the current frame.
+  frame_did_draw_ = false;
+
   scheduler_on_impl_thread_->BeginFrame(args);
 }
 
+void ThreadProxy::DidBeginFrameDeadlineOnImplThread() {
+  // Do not start animations if we skip drawing the frame to avoid
+  // checkerboarding.
+  layer_tree_host_impl_->UpdateAnimationState(
+    frame_did_draw_ || !layer_tree_host_impl_->CanDraw());
+  layer_tree_host_impl_->ResetCurrentFrameTimeForNextFrame();
+}
+
 void ThreadProxy::OnCanDrawStateChanged(bool can_draw) {
   DCHECK(IsImplThread());
   TRACE_EVENT1(
       "cc", "ThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);
   scheduler_on_impl_thread_->SetCanDraw(can_draw);
   layer_tree_host_impl_->UpdateBackgroundAnimateTicking(
       !scheduler_on_impl_thread_->WillDrawIfNeeded());
 }
 
 void ThreadProxy::OnHasPendingTreeStateChanged(bool has_pending_tree) {
   DCHECK(IsImplThread());
   TRACE_EVENT1("cc", "ThreadProxy::OnHasPendingTreeStateChanged",
                "has_pending_tree", has_pending_tree);
-  scheduler_on_impl_thread_->SetHasPendingTree(has_pending_tree);
+  scheduler_on_impl_thread_->SetHasTrees(
+      has_pending_tree,
+      layer_tree_host_impl_->active_tree() ?
+          !layer_tree_host_impl_->active_tree()->root_layer() : true);
+
+  if (!has_pending_tree && !deferred_start_commit_on_impl_thread_.is_null()) {
+    Proxy::ImplThreadTaskRunner()->PostTask(
+        FROM_HERE,
+        deferred_start_commit_on_impl_thread_);
+    deferred_start_commit_on_impl_thread_.Reset();
+  }
 }
 
 void ThreadProxy::SetNeedsCommitOnImplThread() {
   DCHECK(IsImplThread());
   TRACE_EVENT0("cc", "ThreadProxy::SetNeedsCommitOnImplThread");
   scheduler_on_impl_thread_->SetNeedsCommit();
 }
 
 void ThreadProxy::PostAnimationEventsToMainThreadOnImplThread(
     scoped_ptr<AnimationEventsVector> events,
@@ skipping 215 matching lines @@
   TRACE_EVENT0("cc", "ThreadProxy::FinishAllRenderingOnImplThread");
   DCHECK(IsImplThread());
   layer_tree_host_impl_->FinishAllRendering();
   completion->Signal();
 }
 
 void ThreadProxy::ScheduledActionSendBeginFrameToMainThread() {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionSendBeginFrameToMainThread");
   scoped_ptr<BeginFrameAndCommitState> begin_frame_state(
       new BeginFrameAndCommitState);
+
   begin_frame_state->monotonic_frame_begin_time =
       layer_tree_host_impl_->CurrentPhysicalTimeTicks();
   begin_frame_state->scroll_info =
       layer_tree_host_impl_->ProcessScrollDeltas();
 
   if (!layer_tree_host_impl_->settings().impl_side_painting) {
     DCHECK_GT(layer_tree_host_impl_->memory_allocation_limit_bytes(), 0u);
   }
+
+
   begin_frame_state->memory_allocation_limit_bytes =
       layer_tree_host_impl_->memory_allocation_limit_bytes();
   Proxy::MainThreadTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&ThreadProxy::BeginFrameOnMainThread,
                  main_thread_weak_ptr_,
                  base::Passed(&begin_frame_state)));
 
   if (begin_frame_sent_to_main_thread_completion_event_on_impl_thread_) {
     begin_frame_sent_to_main_thread_completion_event_on_impl_thread_->Signal();
@@ skipping 128 matching lines @@
   }
 
   layer_tree_host_->CommitComplete();
   layer_tree_host_->DidBeginFrame();
 }
 
 void ThreadProxy::StartCommitOnImplThread(
     CompletionEvent* completion,
     ResourceUpdateQueue* raw_queue,
     scoped_refptr<cc::ContextProvider> offscreen_context_provider) {
-  scoped_ptr<ResourceUpdateQueue> queue(raw_queue);
-
   TRACE_EVENT0("cc", "ThreadProxy::StartCommitOnImplThread");
   DCHECK(!commit_completion_event_on_impl_thread_);
   DCHECK(IsImplThread() && IsMainThreadBlocked());
   DCHECK(scheduler_on_impl_thread_);
   DCHECK(scheduler_on_impl_thread_->CommitPending());
 
   if (!layer_tree_host_impl_) {
     TRACE_EVENT0("cc", "EarlyOut_NoLayerTree");
     completion->Signal();
+
     return;
   }
 
+  // We defer forced commits while there is a pending tree here.

[brianderson, 2013/07/18 02:02:49]

This code is no longer needed to make composite and readback work, but it could
help us overlap our recording and playback SkPictures as part of the phase 2
items.

+  if (layer_tree_host_impl_->pending_tree()) {
+    NOTREACHED();
+    TRACE_EVENT0("cc", "EarlyOut_DeferringDueToPendingTree");
+    DCHECK(deferred_start_commit_on_impl_thread_.is_null());
+    deferred_start_commit_on_impl_thread_ =
+        base::Bind(&ThreadProxy::StartCommitOnImplThread,
+                   impl_thread_weak_ptr_,
+                   completion,
+                   raw_queue,
+                   offscreen_context_provider);
+    return;
+  }
+
+  scoped_ptr<ResourceUpdateQueue> queue(raw_queue);
+
   if (offscreen_context_provider.get())
     offscreen_context_provider->BindToCurrentThread();
   layer_tree_host_impl_->resource_provider()->
       set_offscreen_context_provider(offscreen_context_provider);
 
   if (layer_tree_host_->contents_texture_manager()) {
     if (layer_tree_host_->contents_texture_manager()->
             LinkedEvictedBackingsExist()) {
       // Clear any uploads we were making to textures linked to evicted
       // resources
@@ skipping 35 matching lines @@
 
   // Complete all remaining texture updates.
   current_resource_update_controller_on_impl_thread_->Finalize();
   current_resource_update_controller_on_impl_thread_.reset();
 
   layer_tree_host_impl_->BeginCommit();
   layer_tree_host_->BeginCommitOnImplThread(layer_tree_host_impl_.get());
   layer_tree_host_->FinishCommitOnImplThread(layer_tree_host_impl_.get());
   layer_tree_host_impl_->CommitComplete();
 
-  layer_tree_host_impl_->UpdateBackgroundAnimateTicking(
-      !scheduler_on_impl_thread_->WillDrawIfNeeded());
-
   next_frame_is_newly_committed_frame_on_impl_thread_ = true;
 
   if (layer_tree_host_->settings().impl_side_painting &&
       layer_tree_host_->BlocksPendingCommit() &&
       layer_tree_host_impl_->pending_tree()) {
     // For some layer types in impl-side painting, the commit is held until
     // the pending tree is activated.  It's also possible that the
     // pending tree has already activated if there was no work to be done.
     TRACE_EVENT_INSTANT0("cc", "HoldCommit", TRACE_EVENT_SCOPE_THREAD);
     completion_event_for_commit_held_on_tree_activation_ =
         commit_completion_event_on_impl_thread_;
     commit_completion_event_on_impl_thread_ = NULL;
   } else {
     commit_completion_event_on_impl_thread_->Signal();
     commit_completion_event_on_impl_thread_ = NULL;
   }
 
   commit_complete_time_ = base::TimeTicks::HighResNow();
   begin_frame_to_commit_duration_history_.InsertSample(
       commit_complete_time_ - begin_frame_sent_to_main_thread_time_);
 
+  // The commit may have added animations, requiring us to start
+  // background ticking.
+  layer_tree_host_impl_->UpdateBackgroundAnimateTicking(
+      !scheduler_on_impl_thread_->WillDrawIfNeeded());
   // SetVisible kicks off the next scheduler action, so this must be last.
   scheduler_on_impl_thread_->SetVisible(layer_tree_host_impl_->visible());
 }
 
 void ThreadProxy::ScheduledActionCheckForCompletedTileUploads() {
   DCHECK(IsImplThread());
   TRACE_EVENT0("cc",
                "ThreadProxy::ScheduledActionCheckForCompletedTileUploads");
   layer_tree_host_impl_->CheckForCompletedTileUploads();
 }
 
 void ThreadProxy::ScheduledActionActivatePendingTreeIfNeeded() {
   DCHECK(IsImplThread());
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionActivatePendingTreeIfNeeded");
   layer_tree_host_impl_->ActivatePendingTreeIfNeeded();
 }
 
 void ThreadProxy::ScheduledActionBeginOutputSurfaceCreation() {
   DCHECK(IsImplThread());
   Proxy::MainThreadTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&ThreadProxy::CreateAndInitializeOutputSurface,
                  main_thread_weak_ptr_));
 }
 
-ScheduledActionDrawAndSwapResult
-ThreadProxy::ScheduledActionDrawAndSwapInternal(bool forced_draw) {
+DrawSwapReadbackResult
+ThreadProxy::ScheduledActionDrawSwapReadbackInternal(
+    bool forced_draw, bool swap_requested, bool readback_requested) {
   TRACE_EVENT0("cc", "ThreadProxy::ScheduledActionDrawAndSwap");
 
-  ScheduledActionDrawAndSwapResult result;
+  DrawSwapReadbackResult result;
   result.did_draw = false;
   result.did_swap = false;
   DCHECK(IsImplThread());
   DCHECK(layer_tree_host_impl_.get());
   if (!layer_tree_host_impl_)
     return result;
 
   DCHECK(layer_tree_host_impl_->renderer());
   if (!layer_tree_host_impl_->renderer())
     return result;
 
-  base::TimeTicks monotonic_time =
-      layer_tree_host_impl_->CurrentFrameTimeTicks();
-  base::Time wall_clock_time = layer_tree_host_impl_->CurrentFrameTime();
-
-  // TODO(enne): This should probably happen post-animate.
-  if (layer_tree_host_impl_->pending_tree()) {
-    layer_tree_host_impl_->ActivatePendingTreeIfNeeded();
-    if (layer_tree_host_impl_->pending_tree())
-      layer_tree_host_impl_->pending_tree()->UpdateDrawProperties();
-  }
-  layer_tree_host_impl_->Animate(monotonic_time, wall_clock_time);
-  layer_tree_host_impl_->UpdateBackgroundAnimateTicking(false);
-
   base::TimeTicks start_time = base::TimeTicks::HighResNow();
   base::TimeDelta draw_duration_estimate = DrawDurationEstimate();
   base::AutoReset<bool> mark_inside(&inside_draw_, true);
 
   // This method is called on a forced draw, regardless of whether we are able
   // to produce a frame, as the calling site on main thread is blocked until its
   // request completes, and we signal completion here. If CanDraw() is false, we
   // will indicate success=false to the caller, but we must still signal
   // completion to avoid deadlock.
 
   // We guard PrepareToDraw() with CanDraw() because it always returns a valid
   // frame, so can only be used when such a frame is possible. Since
   // DrawLayers() depends on the result of PrepareToDraw(), it is guarded on
   // CanDraw() as well.
 
-  bool drawing_for_readback = !!readback_request_on_impl_thread_;
+  bool drawing_for_readback =
+      readback_requested && !!readback_request_on_impl_thread_;
   bool can_do_readback = layer_tree_host_impl_->renderer()->CanReadPixels();
 
   LayerTreeHostImpl::FrameData frame;
   bool draw_frame = false;
-  bool start_ready_animations = true;
 
   if (layer_tree_host_impl_->CanDraw() &&
       (!drawing_for_readback || can_do_readback)) {
     // If it is for a readback, make sure we draw the portion being read back.
     gfx::Rect readback_rect;
     if (drawing_for_readback)
       readback_rect = readback_request_on_impl_thread_->rect;
 
-    // Do not start animations if we skip drawing the frame to avoid
-    // checkerboarding.
     if (layer_tree_host_impl_->PrepareToDraw(&frame, readback_rect) ||
         forced_draw)
       draw_frame = true;
-    else
-      start_ready_animations = false;
   }
 
+  frame_did_draw_ = draw_frame;
+
   if (draw_frame) {
     layer_tree_host_impl_->DrawLayers(
         &frame,
         scheduler_on_impl_thread_->LastBeginFrameOnImplThreadTime());
     result.did_draw = true;
   }
   layer_tree_host_impl_->DidDrawAllLayers(frame);
 
-  layer_tree_host_impl_->UpdateAnimationState(start_ready_animations);
-
   // Check for a pending CompositeAndReadback.
-  if (readback_request_on_impl_thread_) {
-    readback_request_on_impl_thread_->success = false;
+  if (drawing_for_readback) {
+    result.did_readback = false;
     if (draw_frame) {
       layer_tree_host_impl_->Readback(readback_request_on_impl_thread_->pixels,
                                       readback_request_on_impl_thread_->rect);
-      readback_request_on_impl_thread_->success =
+      result.did_readback =
           !layer_tree_host_impl_->IsContextLost();
     }
+    readback_request_on_impl_thread_->success = result.did_readback;
     readback_request_on_impl_thread_->completion.Signal();
     readback_request_on_impl_thread_ = NULL;
-  } else if (draw_frame) {
+  } else if (draw_frame && swap_requested) {
     result.did_swap = layer_tree_host_impl_->SwapBuffers(frame);
 
     if (frame.contains_incomplete_tile)
       DidSwapUseIncompleteTileOnImplThread();
   }
 
   // Tell the main thread that the the newly-commited frame was drawn.
   if (next_frame_is_newly_committed_frame_on_impl_thread_) {
     next_frame_is_newly_committed_frame_on_impl_thread_ = false;
     Proxy::MainThreadTaskRunner()->PostTask(
@@ skipping 71 matching lines @@
   texture_acquisition_completion_event_on_impl_thread_ = completion;
   scheduler_on_impl_thread_->SetMainThreadNeedsLayerTextures();
 }
 
 void ThreadProxy::ScheduledActionAcquireLayerTexturesForMainThread() {
   DCHECK(texture_acquisition_completion_event_on_impl_thread_);
   texture_acquisition_completion_event_on_impl_thread_->Signal();
   texture_acquisition_completion_event_on_impl_thread_ = NULL;
 }
 
-ScheduledActionDrawAndSwapResult
+DrawSwapReadbackResult
 ThreadProxy::ScheduledActionDrawAndSwapIfPossible() {
-  return ScheduledActionDrawAndSwapInternal(false);
+  bool forced_draw = false;
+  bool swap_requested = true;
+  bool readback_requested = false;
+  return ScheduledActionDrawSwapReadbackInternal(
+      forced_draw, swap_requested, readback_requested);
 }
 
-ScheduledActionDrawAndSwapResult
+DrawSwapReadbackResult
 ThreadProxy::ScheduledActionDrawAndSwapForced() {
-  return ScheduledActionDrawAndSwapInternal(true);
+  bool forced_draw = true;
+  bool swap_requested = true;
+  bool readback_requested = false;
+  return ScheduledActionDrawSwapReadbackInternal(
+      forced_draw, swap_requested, readback_requested);
 }
 
+DrawSwapReadbackResult
+ThreadProxy::ScheduledActionDrawAndReadback() {
+  bool forced_draw = true;
+  bool swap_requested = false;
+  bool readback_requested = true;
+  return ScheduledActionDrawSwapReadbackInternal(
+      forced_draw, swap_requested, readback_requested);
+}
+
+
 void ThreadProxy::DidAnticipatedDrawTimeChange(base::TimeTicks time) {
   if (current_resource_update_controller_on_impl_thread_)
     current_resource_update_controller_on_impl_thread_
         ->PerformMoreUpdates(time);
-  layer_tree_host_impl_->ResetCurrentFrameTimeForNextFrame();
 }
 
 base::TimeDelta ThreadProxy::DrawDurationEstimate() {
   base::TimeDelta historical_estimate =
       draw_duration_history_.Percentile(kDrawDurationEstimationPercentile);
   base::TimeDelta padding = base::TimeDelta::FromMicroseconds(
       kDrawDurationEstimatePaddingInMicroseconds);
   return historical_estimate + padding;
 }
 
 base::TimeDelta ThreadProxy::BeginFrameToCommitDurationEstimate() {
   return begin_frame_to_commit_duration_history_.Percentile(
       kCommitAndActivationDurationEstimationPercentile);
 }
 
 base::TimeDelta ThreadProxy::CommitToActivateDurationEstimate() {
   return commit_to_activate_duration_history_.Percentile(
       kCommitAndActivationDurationEstimationPercentile);
 }
 
+void ThreadProxy::PostBeginFrameDeadline(const base::Closure &closure,
+                                         base::TimeTicks deadline) {
+  base::TimeDelta delta = deadline - base::TimeTicks::Now();
+  if (delta <= base::TimeDelta())
+    delta = base::TimeDelta();
+  Proxy::ImplThreadTaskRunner()->PostDelayedTask(FROM_HERE, closure, delta);
+}
+
 void ThreadProxy::ReadyToFinalizeTextureUpdates() {
   DCHECK(IsImplThread());
   scheduler_on_impl_thread_->FinishCommit();
 }
 
 void ThreadProxy::DidCommitAndDrawFrame() {
   DCHECK(IsMainThread());
   if (!layer_tree_host_)
     return;
   layer_tree_host_->DidCommitAndDrawFrame();
@@ skipping 57 matching lines @@
   layer_tree_host_impl_ = layer_tree_host_->CreateLayerTreeHostImpl(this);
   const LayerTreeSettings& settings = layer_tree_host_->settings();
   SchedulerSettings scheduler_settings;
   scheduler_settings.impl_side_painting = settings.impl_side_painting;
   scheduler_settings.timeout_and_draw_when_animation_checkerboards =
       settings.timeout_and_draw_when_animation_checkerboards;
   scheduler_settings.using_synchronous_renderer_compositor =
       settings.using_synchronous_renderer_compositor;
   scheduler_settings.throttle_frame_production =
       settings.throttle_frame_production;
+  scheduler_settings.use_begin_frame_workaround_for_crbug_249806 = true;
   scheduler_on_impl_thread_ = Scheduler::Create(this, scheduler_settings);
   scheduler_on_impl_thread_->SetVisible(layer_tree_host_impl_->visible());
 
   impl_thread_weak_ptr_ = weak_factory_on_impl_thread_.GetWeakPtr();
   completion->Signal();
 }
 
 void ThreadProxy::InitializeOutputSurfaceOnImplThread(
     CompletionEvent* completion,
     scoped_ptr<OutputSurface> output_surface,
@@ skipping 227 matching lines @@
     DCHECK(layer_tree_host_impl_->settings().impl_side_painting);
     completion_event_for_commit_held_on_tree_activation_->Signal();
     completion_event_for_commit_held_on_tree_activation_ = NULL;
   }
 
   commit_to_activate_duration_history_.InsertSample(
       base::TimeTicks::HighResNow() - commit_complete_time_);
 }
 
 }  // namespace cc